Disappointed by POSTNET SERVICES

I paid for an overnight parcel shipment and I was told that it was shipped on the same day (25 November 2019). I expected it the following day (26th November 2019) and it did not arrive. I questioned the lady that was helping me (Sherise) that the parcel has not arrived, she said it was at Koornfontein (which is literally 5 minutes from my house & that was just after 9am). After 12PM I called Postnet and spoke to some lady who claimed even though its an overnight parcel it will arrive after 2-3 days (Mind you I explained that I paid an overnight fee of R342.50 then she gave the phone to Sherise who said she doesn't know when I will get my parcel and that the parcel is at Koornfontein which I explained it is exactly where I am but I have been waiting since 9am. I am so disappointed because I opted for this overnight option as I need the parcel urgently. Now it looks like I paid an overnight fee to be told that my parcel can arrive tomorrow the 28th of November.